In a large skillet, heat 4 tablespoon of the butter over medium heat until melted. Add the shallot and cook until the shallot is translucent. Add the mushrooms, 1 teaspoon of the salt and the pepper. Cook for a minute, stirring. The mushrooms will soak up most of the moisture. Cover the mushrooms and continue to cook on medium, stirring occasionally, until tender – about 5 minutes.

Once tender, uncover, turn the heat up to medium high for one minute. Add the marsala and cook for just 2 minutes. Add the stock, tarragon, parsley, the other 1 teaspoon of salt and 1 teaspoon of the lemon juice. Turn the heat to high and bring the mixture to a simmer, then reduce to medium to medium-low and simmer for 25 minutes. The mixture should have thickened somewhat and reduced at this point.

Once reduced, remove from the heat and stir in the remaining 3 tablespoon of butter 1 at a time and add the last teaspoon of lemon juice. Taste for salt and add if desired.

In a large pot of boiling, salted water, add the pasta and cook until al-dente. Strain the pasta, reserving ½ cup of the water. In a large bowl, toss the pasta with the mushrooms and use pasta water to thin if necessary. Serve.